<?php 
// use wp_list_pages to display parent and all child pages all generations (a tree with parent)
$parent = $post->post_parent;
$args=array(
  'child_of' => $parent,
  'sort_column' => 'menu_order'
);
$pages = get_pages($args);  

  
  foreach ($pages as $page) {
    $pageid = $page->ID;
	$title = $page->post_title;
	$link = get_page_link($pageid); 
	$field = get_post_meta($pageid, 'link-group', true);
	if ( empty($field) ) { ?>
    
	<li class="<?php echo get_post_meta($pageid, 'menu', true); ?>"><a href="<?php echo $link ?>"><?php echo $title ?></a></li>
	
<?php } else { ?>
    <li class="linkGroup"><?php echo get_post_meta($pageid, 'link-group', true) ?></li>
	<li><a href="<?php echo $link ?>"><?php echo $title ?></a></li>
<?php } ?>
	
<?php } ?>